I decided not to go pick a culture straight away, instead, my army of minions was picking up every curiosity that popped up in their line of sight. Gathered plenty of Science and choose Nubians

I was pretty sure I'll have a "free" tech with that much Science but instead, standard 7 turns for any technology

I played a game last week and this did work fine - "Free" tech. Was there any change made in the recent patch? I haven't seen anything in the patch notes.